I would tend to agree with you. There is one aspect of x12 and associated multi-ch content that is IMO a bit different than for 2 ch audio. With only 2 ch, people seem to really get into both of those really deep and it is much easier to focus on any potential flaws in the performance. With x12 channels banging all around you, honestly, there is just no time for such focus. Perhaps just my perception, or lack of ability to have sharp focus on 12 ch at all times, but could be that there are others with the same issue.
Recently was doing some adjustments on the 400W/4ohm Bryston 4B SST that is powering my center and replaced it with 180w/4ohm Rotel RB 1070 (1/3 of Bryston by weight and parts) and honestly could not really tell the difference in 7.4.4 system performing at -10dB to reference volume. I could notice some difference (Bryston being the better one) if I turned off all the other channels though, but that's really not the real world use case though. Probably could still tell the difference in the blind test as know my gear for years, but it seems that for multichannel audio you can get away with lower specs as you just can't perceive each individual channel with the same sharp focus you can for 2 ch audio.